Study Of Frequency Response Of The Electro-Mechanical Transformer Of Digital Valve

With the wide application of computers in the fluid power systems, the 'digitalization' of the fluid power systems and components are becoming an infallible trend. Due to the stepper motor's advantage that it can work well in the open loop system and tend to be controlled by computers, it is widely used in different kinds of control systems as an electro-mechanical transformer.Aimed at the contradiction between the quantitative error and speed of response that exists in the digital valve which uses stepper motor as electro-mechanical transformer, the paper expounds the idea of continual tracing control of stepper motor with the method of pulse-width-modulation. In this way, the quantitative error of the conventional digital valve actuated by the stepper motor is eliminated, and thus both excellent speed of response and accuracy are simultaneously obtained. It has profound significance in the development, research and application of the digital valve which uses stepper motor as its driver.In this paper, the frequency response of the stepper motor as an electro-mechanical transformer is investigated. The main tasks of this paper are as follows:Chapter 1 introduces the history and future of the hydraulic control technology and its components, and the classification and the development of electro-hydraulic digital control technology and its components. Aimed at the contradiction between the quantitative error and speed of response of stepper motor, this chapter gives out the main research content and project of this dissertation.Chapter 2 introduces the working principle, and establishes the mathematical model of the reluctance and the hybrid stepper motor.Chapter 3 presents the idea of continual tracing control of the stepper motor with the method of pulse-width-modulation, and analyses some cases of responses of rotating magnetic field control signals to input sinusoidal waves of different speeds, and the frequency response and convergence of the tracing control signal. It also demonstrates the significance of continual tracing control.In Chapter 4, with the help of MATLAB, SIMULINK and Real-Time workshop, a new experiment platform testing the spool's displacement is designed. This chapter narrates the hardware of the platform. In the end, it introduces the work environment of RTW and...